RU2406262C2 - Decoding of reduced number of channels - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: intermediate presentation of multi-channel signal channels is restored, when mixing parametres are calculated with increase of channels number for mixing with increase of number of channels of transmitted signal mixed with reduction of number of channels, into intermediate presentation of channels, which makes it possible to execute mixing with increase of channels number using the same mixing algorithms with increased number of channels, as well as during multi-channel restoration. This is achieved using facility of parametres recalculation for calculation of mixing parametres with increase of channels number, in which parametres containing information on channels that are not included in intermediate presentation of channels are also taken into account.

EFFECT: decoding of signal with high efficiency and high fidelity of reproduction.

23 cl, 8 dwg

Description

FIELD OF THE INVENTION

The present invention relates to the field of decoding audio signals, in particular to decoding signals obtained by parametric multi-channel mixing of the original multi-channel signal with a reduction in the number of channels (downmix) to several channels, the number of which is less than the number of channels of the original multi-channel signal.

BACKGROUND

Recent advances in audio coding have made it possible to reconstruct a multi-channel representation of an audio signal based on a stereo (or mono) signal and associated control data. These methods differ significantly from previous matrix-based solutions, for example, from the Dolby Prologic system, because they transmit additional control data to control the restoration of surround channels based on transmitted mono or stereo channels, which is also called mixing with increase in the number of channels (upmix).

Therefore, such a device for parametric decoding of multi-channel audio, for example, MPEG surround sound (MPEG Surround), restores N channels based on M transmitted channels, where N> M, and additional control data. The transmission rate of additional control data is significantly lower than the transmission rate of all N channels, which makes coding very efficient, while ensuring compatibility with both M-channel devices and N-channel devices.

These parametric surround sound encoding methods typically include parameterization of the surround signal based on the difference between the intensity between the channels (IID) and the coherence between the channels (ICC). These parameters describe the power relations and the correlation between the pairs of channels during the mixing process with an increase in the number of channels. Other parameters are also used in the prior art, including prediction parameters used to predict intermediate or output channels during a mixing procedure with an increase in the number of channels.

Two well-known examples of such multi-channel coding are binaural coding (BCC) and MPEG surround coding (MPEG surround). With binaural coding (BCC), several input audio channels are converted to spectral representation using a transform based on a discrete Fourier transform (DFT) with overlapping windows. Then, the resulting uniform spectrum is divided into non-overlapping segments. Each segment has a bandwidth proportional to the equivalent width of a rectangular frequency band (ERB). Then, spatial parameters called ICLD (level difference between channels) and ICTD (time difference between channels) are estimated for each segment. The ICLD parameter describes the level difference between two channels, and the ICTD parameter describes the time difference (phase shift) between two signals of different channels. Level differences and time differences are set for each channel relative to the common reference channel. After receiving these parameters, discretization and coding of parameters for transmission are performed.

With binaural coding (BCC), individual parameters are evaluated relative to a single reference channel. Other parametric surround sound encoding systems, such as MPEG surround surround sound (MPEG surround), use a tree structure parameterization. This means that the parameters are no longer evaluated relative to one single common reference channel, but rather relative to different reference channels, which may even be a combination of channels of the original multi-channel signal. For example, if there is a 5.1 system signal in the channel, parameters can be estimated between the combination of the front channels and between the combination of the rear channels.

It goes without saying that for parametric coding schemes, backward compatibility with already existing sound reproduction standards is also highly desirable. For example, in the presence of a monophonic signal mixed with a reduction in the number of channels, it is also desirable to provide the possibility of creating a stereo signal with high fidelity. This means that a monophonic signal mixed with a reduction in the number of channels must be mixed with an increase in the number of channels in a stereo signal using the additionally transmitted parameters in the best possible way.

One common problem with multi-channel coding is energy conservation during mixing with an increase in the number of channels, since the dominant factor in a person’s perception of the position of a sound source in space is the volume of the signal, that is, the energy contained in the signal. Therefore, when reproducing the signal, extreme care must be taken to ensure the correct volume of each restored channel, for example, to avoid introducing distortions that greatly degrade the perception quality of the restored signal. Since during mixing, with a reduction in the number of channels, summation of the amplitudes of the signals is usually performed, the possibility of interference arises, which is described by the correlation or coherence parameter.

When it comes to recovering a reduced number of channels (several channels whose number is less than the original number of channels of a multi-channel signal), processing in circuits similar to the binaural coding scheme (BCC) is simple because each parameter is transmitted with respect to the same one reference channel. Therefore, having information about the reference channel, the most significant information (a measure of absolute energy) can easily be obtained for each channel necessary for mixing with an increase in the number of channels. Thus, a reduced number of channels can be restored without having to first perform a full multi-channel signal recovery. Thus, energy calculations for energy values of a multi-channel signal are simpler in a binaural coding scheme (BCC) using separate variables rather than products of variables, but this is only the first step. When it comes to obtaining energy values and correlations of a reduced number of channels, which should be as close to partial mixing of the original multi-channel signals with as few channels as possible, the level of complexity when encoding in MPEG format with surround sound (MPEG surround) and when binaural coding (BCC) is comparable.

In contrast, in a tree structure, such as in the MPEG surround format (MPEG surround), a parameterization is used in which the corresponding information for each individual channel is not contained in one parameter. Therefore, in the prior art, restoration of a reduced number of channels requires restoration of a multi-channel signal, after which mixing is performed with a reduction in the number of channels to a reduced number of channels, without violating the requirements for energy conservation. This has an obvious disadvantage of extremely high computational complexity.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a concept for more efficiently obtaining a reduced number of channels from a parametric multi-channel signal.

According to a first aspect of the present invention, this task is achieved by means of a parameter calculation means for obtaining mixing parameters with an increase in the number of channels for performing mixing with an increase in the number of channels of a signal mixed with a reduction in the number of channels, into an intermediate representation of the channels of a multi-channel signal having a larger number of channels, than a signal mixed with a reduction in the number of channels, and fewer channels than a multi-channel signal nal, and the signal mixed with a reduction in the number of channels has associated multichannel parameters describing the spatial characteristics of the multichannel signal, while the multichannel signal contains channels not contained in the intermediate representation of the channels, and the multichannel parameters contain information about channels not contained in the intermediate the channel representation, and the parameter calculation means, comprises the parameter recalculation tool, intended to obtain mixing parameters with velicheniem number of channels of the multichannel parameters using the parameters c, containing information on the channels not included in the intermediate channel representation.

According to a second aspect of the present invention, this objective is achieved by means of a channel recovery means, which is provided with a parameter recovery means comprising parameter calculating means for obtaining mixing parameters by increasing the number of channels for mixing with increasing the number of channels of a signal mixed with a reduction in the number of channels into an intermediate representation of channels of a multi-channel signal having a larger number of channels than the signal are mixed with a reduction in the number of channels, and a smaller number of channels than a multichannel signal, the signal mixed with a reduction in the number of channels has associated multichannel parameters describing the spatial characteristics of the multichannel signal, while the multichannel signal contains channels not contained in the intermediate representation of the channels, and multichannel parameters contain information about channels not contained in the intermediate representation of the channels, and the means for calculating the parameters contains media parameter recalculation, intended to obtain mixing parameters with increasing the number of channels from multichannel parameters using parameters containing information about channels not contained in the intermediate representation of channels, and mixing means with increasing the number of channels, designed to obtain an intermediate representation of channels using mixing parameters with an increase in the number of channels and a signal mixed with a decrease in the number of channels.

According to a third aspect of the present invention, this object is achieved by a method for generating mixing parameters with increasing the number of channels for mixing with increasing the number of channels of a signal mixed with a reduction in the number of channels into an intermediate representation of channels of a multi-channel signal having a larger number of channels than a signal mixed with a reduction the number of channels, and fewer channels than a multi-channel signal, the signal mixed with a reduction in the number each channel has multichannel parameters associated with it that describe the spatial characteristics of the multichannel signal, while the multichannel signal contains channels not contained in the intermediate channel representation, and the multichannel parameters contain information about channels not contained in the intermediate channel representation, and the method comprises the following operation : get mixing parameters with an increase in the number of channels from multichannel parameters using parameters containing channel information alah not contained in the intermediate representation of the channels.

According to a fourth aspect of the present invention, this objective is achieved with a sound receiver or sound reproducing device, wherein the receiver or sound reproducing apparatus comprises parameter calculating means for obtaining mixing parameters with an increase in the number of channels for mixing with an increase in the number of channels of a signal mixed with a reduction in the number channels, in an intermediate representation of the channels of a multi-channel signal having a larger number of channels than a signal mixed with a reduction in the number of channels, and a smaller number of channels than a multi-channel signal, a signal mixed with a reduction in the number of channels has associated multi-channel parameters describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels not contained in the intermediate channel representation, and multichannel parameters contain information about the channels not contained in the intermediate channel representation, and the tool is calculated I parameters comprises means for allocation of parameters for obtaining the mixing parameters to increase the number of channels of the multichannel parameters using the parameters having information on channels not included in the intermediate channel representation.

According to a fifth aspect of the present invention, this objective is achieved by a method for receiving or reproducing sound, including a method for generating mixing parameters by increasing the number of channels for mixing with increasing the number of channels of a signal mixed with a reduction in the number of channels into an intermediate representation of channels of a multi-channel signal having a larger the number of channels than a signal mixed with a reduction in the number of channels, and fewer channels than a multi-channel with drove, and the signal mixed with the reduction in the number of channels has associated with it multi-channel parameters describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels not contained in the intermediate representation of the channels, and the multi-channel parameters contain information about channels not contained in the intermediate presentation of channels, and the method comprises the following operation: mixing parameters are calculated with an increase in the number of channels from multi-channel parameter in using the parameters having information on channels not included in the intermediate channel representation.

The present invention is based on the discovery of the fact that the intermediate representation of the channels of a multi-channel signal can be restored with high efficiency and high fidelity when mixing parameters are obtained with an increase in the number of channels for mixing the transmitted signal mixed with a decrease in the number of channels with an increase the number of channels in the intermediate representation of channels, allowing mixing with an increase in the number of channels using vaniem same mixing algorithms with an increase in the number of channels in the case of recovery of the multichannel signal. This can be achieved when a parameter recalculation tool is used to obtain mixing parameters with an increase in the number of channels, while also taking into account parameters containing information about channels not contained in the intermediate channel representation.

In one embodiment of the present invention, a decoding device is capable of recovering a stereo output signal from a parametric mixing with a reduction in the number of channels of a multi-channel signal with 5 channels, wherein the result of a parametric mixing with a reduction in the number of channels comprises a monophonic signal mixed with a reduction in the number of channels and corresponding multi-channel parameters . According to the present invention, to mix a stereo signal with an increase in the number of channels, spatial parameters are combined to obtain mixing parameters with an increase in the number of channels, and this combination also takes into account multichannel parameters not associated with the left front or right front channel. Therefore, absolute power values for stereo channels mixed with increasing number of channels can be obtained, and a measure of coherence between the left and right channels can be obtained, which makes it possible to stereo restore a multi-channel signal with high fidelity. In addition, a coherence between channels (ICC) parameter and a parameter characterizing the level difference between channels (CLD) are obtained, which allows mixing with increasing the number of channels using existing algorithms and implementations. Using channel parameters that are not associated with the restored stereo channels allows you to save energy in the signal with higher accuracy. This is of the greatest importance, since uncontrolled changes in volume to the greatest extent violate the quality of the reproduced signal.

In general, the application of the idea of the present invention provides the ability to restore a stereo signal mixed with an increase in the number of channels from a monophonic signal mixed with a decrease in the number of channels from a multi-channel signal, without the need for intermediate full restoration of the multi-channel signal, which is the case with the methods of the prior art. Obviously, in this way, the computational complexity in the decoding apparatus can be significantly reduced. In addition, the use of multichannel parameters associated with channels not contained in a signal mixed with an increase in the number of channels (i.e., in a signal having a left front channel and a right front channel) provides the possibility of such reconstruction, which does not introduce any additional distortions or volume changes, but, on the contrary, completely saves the energy of the signal. In a more specific presentation, the energy ratio between the left and right restored channels is calculated from the many available multichannel parameters, while multichannel parameters not associated with the left front channel and the right front channel are also taken into account. Obviously, the ratio of the volume between the left and right restored (mixed with an increase in the number of channels) channels is the dominant factor for the quality of listening to the restored stereo signal. Without using the idea of the present invention, restoration of channels having exactly the correct energy ratio in the tree structures discussed in this document is impossible.

Therefore, the implementation of the idea of the present invention allows for high-quality stereo playback of a multi-channel signal mixed with a reduction in the number of channels, based on multi-channel parameters that are not obtained for accurate reproduction of a stereo signal.

It should be noted that the idea of the present invention can also be used when the number of reproduced channels is other than two, for example, when it is also necessary to perform restoration of the central channel with high accuracy, which is the case in some playback modes.

A more detailed overview of multi-channel coding schemes (in particular, based on tree structures) from the prior art will be given below to summarize the great benefits of the idea of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a description of preferred embodiments of the present invention with reference to the accompanying drawings, which depict the following:

in FIG. 1 shows examples of parameterization methods based on a tree structure;

in FIG. 2 shows examples of decoding schemes with a tree structure;

in FIG. 3 shows an example of a multi-channel coding apparatus of the prior art;

in FIG. 4 shows examples of decoding devices of the prior art;

in FIG. 5 shows an example of stereo reconstruction of a multi-channel signal mixed with a reduction in the number of channels from the prior art;

in FIG. 6 is a block diagram of an example of a parameter calculating tool provided in the present invention;

in FIG. 7 shows an example of a channel recovery tool provided in the present invention; and

in FIG. 8 shows an example of a receiver or sound reproducing apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following is a description of the idea of the present invention, mainly in relation to encoding in MPEG format, but it is also well applicable to other schemes based on parametric encoding of multi-channel signals. That is, the embodiments described below are merely illustrative examples of the principles of the present invention for decoding a reduced number of channels for multi-channel systems with a tree structure. It is understood that for those skilled in the art, the possibility of modifications and changes to the devices and details described herein is obvious. Therefore, it is intended that the present invention be limited only by the scope of the claims below, and not by the specific details presented here by describing and explaining embodiments of the invention.

As mentioned above, in some parametric surround coding systems, for example in MPEG surround format (MPEG surround), a tree structure parameterization is used. Such parameterization is shown schematically in the drawings of FIG. 1 and FIG. 2.

In FIG. 1 shows two ways of parameterizing the scenario of standard sound channels of a 5.1 system having a left front channel 2, a central channel 3, a right front channel 4, a left surround channel 5 and a right surround channel 6. It is possible, but not necessary, that channel 7 of low frequency amplification (LFE) (hereinafter referred to as the VLF channel) may also be present.

Typically, individual channels or channel pairs are characterized relative to each other by multichannel parameters, such as, for example, the coherence between channels (ICC) parameter and the level parameter (parameter characterizing the level difference between channels, CLD). In the next paragraph, a brief explanation of possible parameterization methods will be given, and then the resulting decoding schemes with a tree structure will be illustrated with reference to FIG. 2.

In the example shown at the top of FIG. 1 (parameterization type 5-1-5 ₁ ), a multi-channel signal is described by a parameter characterizing the level difference between the channels (CLD), and a coherence parameter between the channels (ICC), which describe the relationship between the left surround channel 5 and the right surround channel 6 , the left front channel 2 and the right front channel 4, and between the center channel 3 and the low-frequency amplification channel 7. However, since the entire configuration should be mixed with a reduction in the number of channels in one single monaural channel, additional parameters are required to fully describe the set of channels. Therefore, additional parameters (CLD ₁ , ICC ₁ ) are used that describe the relationship between the combination of the VLF speaker 7 and the center speaker 3 with the combination of the left front channel 2 and the right front channel 4. In addition, another additional set of parameters is required (CLD ₀ , ICC ₀ ), these parameters describe the relationship between the combined surround channels 5 and 6 and the remaining channels of the multi-channel signal.

For the parameterization shown at the bottom of the drawing (parameterization of type 5-1-5 ₂ ), parameters are used that describe the relationship of the left front channel 2 with the left surround channel 5, the right front channel 4 with the right surround channel 6 and the center channel 3 s channel 7 amplification of low frequencies. Additional parameters (CLD ₁ and ICC ₁ ) describe the relationship between the combination of left channels 2 and 5 and the combination of right channels 4 and 6. Another set of parameters (CLD ₀ and ICC ₀ ) describes the relationship between the combination of center channel 3 and VLF channel 7, and a combination of the remaining channels.

In FIG. 2 illustrates the coding concepts underlying the various parameterization methods of FIG. 1. On the side of the decoding device in the tree structure, the so-called OTT modules ("one to two", hereinafter - OKD) are used. Each OKD module mixes a monophonic signal with an increase in the number of channels, converting it into two output signals. When decoding, parameters for OKD modules should be applied in the reverse order of their encoding. Therefore, in the tree structure of type 5-1-5 ₁ , the OKD module 20 receiving the signal 22 (m), mixed with a reduction in the number of channels, operates in such a way that it uses the parameters CLD ₀ and ICC ₀ to obtain two channels, one of which is a combination of the left surround channel 5 and the right surround channel 6, and the other channel is still a combination of the remaining channels of the multi-channel signal.

Accordingly, the OKD module 24, using CLD ₁ and ICC ₁ , receives the first channel, which is a combined channel from the central channel 3 and low-frequency channel 7, and the second channel, which is a combination of the left front channel 2 and the right front channel 4. In the same way OKD module 26 receives the left surround channel 5 and the right surround channel 6 using CLD ₂ and ICC ₂ . The OKD module 27 receives the center channel 3 and the low-frequency channel 7 using CLD ₄ , and the OKD module 28 receives the left front channel 2 and the right front channel 4 using CLD ₃ and ICC ₃ . Finally, a full set of channels 30 is restored from a single monaural channel 22 mixed with a reduced number of channels. For a tree structure of type 5-1-5 _{2, the} general layout of OKD modules is equivalent to a tree structure 5-1-5 ₁ . However, single OKD modules receive different channel combinations, and these channel combinations correspond to the parameterization shown in FIG. 1 for case 5-1-5 ₂ .

From FIG. 1 and 2, it becomes apparent that the tree structure of the various parameterization methods is only a visualization for the parameterization used. In addition, it is important to note that individual parameters are parameters that describe the relationship between different channels, in contrast, for example, to a binaural coding scheme (BCC) in which similar parameters are obtained with respect to a single reference channel.

Therefore, in the shown parametrization methods, individual channels cannot be obtained simply using the parameters associated with the OKD modules in the visualization, but, in addition, some or all other parameters must be taken into account.

The tree structure of the parameterization is only a visualization of the actual signal flow or real processing shown in FIG. 3, which illustrates the mixing of a transmitted small number of channels with an increase in the number of channels, performed by matrix multiplication. In FIG. 3 shows decoding based on a received channel 40 mixed with a reduction in the number of channels. Channel 40, mixed with a reduction in the number of channels, is introduced into the mixing unit 42 with an increase in the number of channels, obtaining a reconstructed multi-channel signal 44, the composition of the channels being different depending on the parameterization methods used. However, the matrix elements of the matrix used by the recovery unit 42 are obtained directly from the tree structure. The recovery unit 42, for illustrative purposes only, can be further divided into components, one of which is a preliminary decorrelator matrix 46, through which additional decorrelated signals are received from the transmitted channel 40. They are then introduced into the mixing matrix 48, by means of which multichannel signals 44 by mixing the individual input channels.

As shown in FIG. 4, a straightforward approach to reducing the number of reconstructed channels is simply to “trim” the tree structure of the one-to-two modules. In FIG. 4 dashed lines illustrate a possible “pruning” of tree structures; during this “pruning”, OKD modules located on the right side of the tree structure are not used during restoration, thus reducing the number of channels at the output. However, when using the parameterization methods of the prior art shown in FIG. 1 and 2, which are presented because they provide low bit rate coding with the highest possible quality, obtaining a stereo output signal that correctly displays the channels of the left side of the original multi-channel signal mixed with a reduction in the number of channels, and the channels of the right side of the original multi-channel signal, mixed with a reduction in the number of channels is not possible simply by “trimming”. In FIG. 5 shows an approach to creating a stereo output signal from the above-described signals according to the prior art, in which an obvious approach is used, when the multi-channel signal is completely restored first before mixing the signal with reduction in the number of channels, converting it into a stereo representation using an additional mixer 60 with a reduction in the number of channels. Obviously, this approach has several disadvantages, for example, high complexity and low sound quality.

The following is a description of the solution to the aforementioned problem of obtaining a stereo output signal from a monophonic signal mixed with a reduction in the number of channels and parameters of parametric surround sound during parameterization, which naturally does not provide support for “trimming” to a stereo output signal, which is obtained for the general case. Then, two specific embodiments of the invention are described that demonstrate the use of the idea of the present invention in the parameterization methods described above. Thus, solutions to the problem of obtaining a stereo output signal from a monophonic signal mixed with a reduction in the number of channels and parameters of parametric surround sound during parameterization, which does not provide support for “trimming” to a stereo output signal, are provided.

A brief description of the general approach to parameter recalculation will be given below. In particular, it is applicable for the case of calculating the parameters of a stereo output signal from an arbitrary number of channels of multichannel sound, which is equal to N. In addition, it is assumed that the sound signal is described by its representation over subbands obtained using a filter unit, which can be real or complex modulated.

в поддиапазоне сформированы из выборок звуковых каналов

из поддиапазона и декоррелированных выборок звуковых каналов

из поддиапазона в соответствии с операцией матричного микширования с увеличением количества каналов Let all the considered signals be finite vectors of samples from the subband corresponding to the time-frequency fragment determined by spatial parameters, and let the samples of the reconstructed multichannel audio signal

in subband are formed from samples of sound channels

from sub-band and decorrelated samples of audio channels

from a subband in accordance with the operation of matrix mixing with an increase in the number of channels

,

,

имеет размер

и отображает суммарное действие матриц M1 и M2 из Фиг. 3 и, по существу, блока 42 микширования с увеличением количества каналов. Общий способ достижения надлежащих параметров мощности и корреляции версии, смикшированной с сокращением количества каналов до

каналов исходных выборок из поддиапазона многоканального звукового сигнала состоит в формировании ковариационной матрицы виртуального микширования с сокращением количества каналов, определяемой матрицей

микширования с сокращением количества каналов, которая состоит из

элементовAll signals are considered row vectors. Matrix

has size

and displays the combined effect of the matrices M1 and M2 of FIG. 3 and essentially a mixing unit 42 with an increase in the number of channels. A general way to achieve the proper power parameters and correlation of the version mixed with reducing the number of channels to

channels of the original samples from the subband of the multi-channel audio signal consists in the formation of a covariance matrix of virtual mixing with a reduction in the number of channels determined by the matrix

mixing with a reduction in the number of channels, which consists of

elements

This covariance matrix can be calculated by multiplying by the transposed complex conjugate value as follows:

,

,

часто является известной из характеристик декорреляторов и переданных параметров.where is the internal covariance matrix

often known from the characteristics of decorrelators and transmitted parameters.

, и в этом случае эта внутренняя ковариационная матрица часто фактически равна единичной матрице размера

. Поэтому для стереофонического выходного сигнала, где

=2, параметр, характеризующий разность уровней между каналами (CLD), и параметр когерентности между каналами (ICC) могут быть считаны из следующего выражения:An important special case where this is done is when

, and in this case this internal covariance matrix is often actually equal to the identity matrix of size

. Therefore for stereo output, where

= 2, the parameter characterizing the level difference between the channels (CLD), and the coherence parameter between the channels (ICC) can be read from the following expression:

in the sense that

комплексное скалярное произведение и норма вектора в квадрате определяются следующим выражением:It should be noted that hereinafter, the following notation is used. For complex vectors

the complex scalar product and the norm of the vector squared are determined by the following expression:

where the asterisk indicates complex conjugation.

Two embodiments of the present invention should be obtained below for the various parameterization methods (5-1-5 ₁ and 5-1-5 ₂ ) shown in FIG. 1 and 2. In embodiments of the present invention, the idea is as follows: in order to output stereo signals based on monophonic signals mixed with a reduction in the number of channels and the corresponding parameters of the MPEG format with surround sound (MPEG surround) (multi-channel parameters), it is necessary to recalculate the mixing parameters with an increase in the number of channels into a single set of parameters consisting of a parameter characterizing the level difference between the channels (CLD) and the parameter erentnosti between channels (ICC), which can be used for directly receiving a stereo signal from the mono downmix signal by increasing the number of channels.

In addition, it is assumed that the processing of individual audio channels is performed frame-by-frame, that is, in discrete time intervals. Thus, speaking of the values of power or energy contained in one channel, the term “power” or “energy” should be understood as energy or power contained in one frame of one particular channel.

значениями выборок энергия E в кадре может быть представлена, например, посредством суммы квадратов значений выборок из поддиапазона в кадреTypically, parameters such as, for example, a parameter characterizing the level difference between channels (CLD), and the coherence parameter between channels (ICC) are also applicable for one single frame. In frame with

the values of the samples, the energy E in the frame can be represented, for example, by the sum of the squares of the values of the samples from the subband in the frame

The values of the level difference between the channels (CLD) transmitted and used to calculate the mixing parameters with an increase in the number of channels for mixing with an increase in the number of channels of a signal M mixed with a decrease in the number of channels into an intermediate (stereo) representation of channels from a multi-channel signal are determined as follows:

и

обозначают мощность рассматриваемых сигналов в кадре, для которого должен быть получен параметр, характеризующий разность уровней между каналами (CLD).Where

and

denote the power of the considered signals in the frame, for which a parameter characterizing the level difference between the channels (CLD) should be obtained.

, где

=0,1,2,3.Therefore, for case 5-1-5 _1, to obtain the channel power values normalized to the power of a monophonic channel m mixed with a reduction in the number of channels, four parameters characterizing the level difference between the channels (CLD) can be used:

where

= 0,1,2,3.

.

.

Channel gains are determined by the following expressions:

and

и

в смысле поиска надлежащих оценочных значений нормированных значений мощности и корреляции стереофонических каналов (промежуточного представления каналов), сформированных следующим образом:The ultimate goal is to get optimal stereo channels.

and

in the sense of searching for appropriate estimated values of normalized power values and correlation of stereo channels (intermediate representation of channels) formed as follows:

,

, Where

, provided that

,

, Where

, provided that

,

where the weighting factor of the mixing of the Central channel with a reduction in the number of channels is

.

.

The calculation of power values based on this assumption gives the following result:

, где

=0,1 самым целесообразным вариантом является следующий: предполагают, что оба канала: объединенный левый канал

и объединенный правый канал

, являются некоррелированными с центральным каналом

. Следовательно, оценку нормированных значений мощности выходных стереофонических каналов производят следующим образом: It turns out that instead of trying to include correlation information, the media of which are the parameters

where

= 0.1, the most appropriate option is the following: assume that both channels: the combined left channel

and united right channel

are uncorrelated with the central channel

. Therefore, the normalized power values of the output stereo channels are estimated as follows:

After the output channel power values are obtained, the desired parameter characterizing the level difference between the channels (CLD) can be easily calculated using the above definition of the parameter characterizing the level difference between the channels (CLD).

According to the idea of the present invention, an inter-channel coherence parameter (ICC) is obtained, enabling stereo mixing with an increase in the number of channels. The correlation between the two output channels of the signal is determined by the following expression:

и объединенный правый канал

являются некоррелированными с центральным каналом

, и, кроме того, в том, что каналы объемного звучания являются некоррелированными с передними каналами. Эти предположения могут быть выражены следующим образом:An attractive set of simplifying assumptions here again is that the combined left channel

and united right channel

are uncorrelated with the central channel

, and moreover, that the surround channels are uncorrelated with the front channels. These assumptions can be expressed as follows:

зависит от двух параметров когерентности между каналами (ICC), которыми являются параметры

, где

=2,3, описывающие нормированные значения корреляции между левыми/правыми каналами, и имеет следующий вид:The resulting estimated value for

depends on two parameters of coherence between channels (ICC), which are the parameters

where

= 2,3, which describe the normalized correlation between the left / right channels, and has the following form:

and this expression can be written as follows:

Thus, the final correlation value depends on numerous parameters of multichannel parameterization, which allows signal reconstruction with high fidelity of reproduction. Finally, an inter-channel coherence parameter (ICC) is obtained using the following formula:

, смикшированного с сокращением количества каналов, в процессе стереофонического микширования с увеличением количества каналов, необходим коэффициент регулировки усиления для глобального масштабирования.According to the idea of the present invention, the power distribution between the restored channels is restored with high accuracy. However, there may be an additional need for global power scaling applied to both channels to ensure total energy conservation. Since the relative distribution of energy between the channels is essential for the spatial perception of the reconstructed signal, global scaling can degrade the perception quality of the reconstructed signal. It must be emphasized that global scaling is global only within the time-frequency fragment determined by the parameter. This means that improper scaling will have a local effect on the signal at the scale of fragments determined by the parameter. In other words, gain factors are applied that depend on both frequency and time, which lead to both distortions due to spectral “bleaching” and distortions due to time modulation. To guarantee the preservation of monophonic channel power

, mixed with a reduction in the number of channels, in the process of stereo mixing with an increase in the number of channels, a gain adjustment factor is necessary for global scaling.

, равен

=1 для конфигурации 5-1-5₁, так как

However, this coefficient defined by the expression

is equal

= 1 for the configuration 5-1-5 ₁ , since

As another embodiment of the invention, the following paragraphs provide a brief description of the application of the idea of the present invention to a tree structure of type 5-1-5 ₂ . To create a stereo signal with high fidelity, the first two sets of parameters are considered, consisting of a parameter characterizing the level difference between the channels (CLD) and a coherence parameter between the channels (ICC), which correspond to the upper branches of the tree structure.

, где

=0,1, для получения нормированных значений мощности объединенных левого и правого каналов, и центрального каналаFirst, two parameters are used that characterize the level difference between the channels (CLD), which are denoted as

where

= 0.1, to obtain normalized power values of the combined left and right channels, and the central channel

,

,

where the channel gains are determined by the following expressions:

and

The task is to obtain the values of power and correlation of channels mixed with a reduction in the number of channels,

,

,

,

,

where the weighting factor of the mixing of the Central channel with a reduction in the number of channels is

.

.

The calculation of power values based on this assumption gives the following result:

,

,

.

.

и

и между каналами

и

являются теми же самыми, что и заданный параметр

между каналами

и

. Это предположение приводит к следующим оценочным значениям:A reasonable assumption here is that both coherence parameters (ICC) between channels

and

and between channels

and

are the same as the given parameter

between channels

and

. This assumption leads to the following estimates:

therefore, the estimated normalized power values become equal

и

, может быть получен желательный параметр, характеризующий разность уровней между каналами (CLD)As in the previous embodiment, knowing the power values

and

, the desired parameter characterizing the level difference between the channels (CLD) can be obtained

The calculation of the correlation and, finally, the coherence parameter between the channels (ICC), begin with a general definition of the correlation value

All the necessary information is available from the parameters of the tree structure of type 5-1-5 ₂ , since

The final results can be written as follows:

регулировки усиления определяется следующим выражением:Ratio Required

gain control is determined by the following expression:

It can be noted that the generated parameters: the parameter characterizing the level difference between the channels (CLD) and the coherence parameter between the channels (ICC) can be additionally discretized to provide the possibility of using lookup tables in the decoding device to create a mixing matrix with an increase in the number of channels instead of performing complex computing. This further increases the efficiency of the mixing method with an increase in the number of channels.

As a rule, mixing with an increase in the number of channels is possible using the existing OKD modules. This has the advantage that the idea of the present invention can be easily implemented in existing decoding scenarios.

The mixing matrix with increasing number of channels can usually be described as follows:

Where

and where

and

Therefore, having obtained the level difference between channels (CLD) parameter and the coherence between channels (ICC) parameter according to the present invention, mixing with increasing the number of channels can be performed, which converts the transmitted signal mixed with a reduction in the number of channels into a stereo signal with high fidelity with using standard mixing modules with an increase in the number of channels.

In yet another embodiment of the invention, the channel recovery tool of the present invention comprises parameter calculating means for obtaining mixing parameters with increasing the number of channels, and mixing means with increasing the number of channels, intended for obtaining an intermediate representation of channels using mixing parameters with increasing the number of channels and a transmitted signal mixed with a reduction in the number of channels.

The idea of the present invention is again schematically illustrated in FIG. 6, which shows a parameter calculator 502 proposed in the present invention, receiving a plurality of inter-channel coherence parameters (ICC) 504 and a plurality of parameters 506 characterizing a level difference between channels (CLD). According to one embodiment of the present invention, the parameter calculator 502 proposed in the present invention obtains one parameter 508 characterizing the level difference between the channels (CLD) and one parameter 510 between channel coherence (ICC) to restore the stereo signal using also multi-channel parameters ( ICC and CLD) containing information about channels that are not contained in stereo mixing channels with an increase in the number of channels, or that are not associated with these channels Lamy.

It can be noted that the idea of the present invention can be easily adapted for mixing scenarios with an increase in the number of channels including more than two channels. The term "mixing with an increase in the number of channels" in this sense is usually defined as an intermediate representation of the channels of a multi-channel signal, where the intermediate representation of the channels has more channels than a signal mixed with a reduction in the number of channels and fewer channels than a multi-channel signal. One common scenario is a configuration in which an additional center channel is restored.

Application of the idea of the present invention is again schematically depicted in FIG. 7, which shows a parameter calculator 502 proposed in the present invention and a one-to-two block (520). To the OKD block 520, the transmitted monophonic signal 522 is supplied as an input signal, as has already been shown in detail in FIG. 6. In the proposed in the present invention means 502 calculation of parameters receives several values 504 between the coherence between channels (ICC) and several values 506 of the difference between the channels (CLD) to obtain one parameter 508, characterizing the difference between the channels (CLD), and one parameter 510 Inter-Channel Coherence (ICC).

The single parameters, which are parameter 508, which characterizes the level difference between the channels (CLD), and parameter 510 coherence between the channels (ICC), are entered into the OKD module 520 to control mixing with increasing the number of channels of monaural signal 522, mixed with a reduction in the number of channels. Thus, at the output of the OKD module 520, a stereo signal 524 can be obtained in the form of an intermediate representation of the channels of a multi-channel signal.

In FIG. 8 illustrates a receiver proposed in the present invention or a sound reproducing apparatus 600 according to the present invention, comprising a sound decoding apparatus proposed in the present invention 601, an input 602 for inputting a bit stream and an output 604 for outputting sound.

A bitstream may be provided to an input 602 of a receiver / audio reproducing device 600 of the present invention. Then, the decoding device 601 decodes the bitstream, and the decoded signal is output through or output from the receiver 60 / audio reproducing device 600 of the present invention.

Despite the fact that the idea of the present invention has been set forth mainly in relation to MPEG surround coding (MPEG surround), it goes without saying that it is by no means limited to the use of parametric coding for a particular scenario. Due to the high adaptability of the idea of the present invention, it can also be easily applied to other coding schemes, for example, channel configurations of type 7.1 or 7.2 or to binaural coding schemes (BCC).

Although MPEG encoding embodiments of the present invention have introduced some simplifying assumptions for generating a common parameter between the level differences between channels (CLD) and a coherence parameter between channels (ICC), these assumptions are not required condition. It goes without saying that it is also possible not to introduce these simplifications.

Depending on the specific requirements for implementing the methods proposed in the present invention, the methods of the present invention can be implemented in hardware or in the form of software. They can be implemented using a digital storage medium, in particular a disk, which is a universal digital disk (DVD) or compact disc (CD), containing control signals stored on it, read by electronic means that interact with a programmable computer system in this way that ensure the implementation of the methods proposed in the present invention. Therefore, the present invention is typically a computer program product with program code stored on a machine-readable medium, and the program code operates in such a way as to implement the methods of the present invention when the computer program product is executed on a computer. In other words, the methods proposed in the present invention are therefore implemented by means of a computer program comprising program code for executing at least one of the methods proposed in the present invention when the computer program is executed on a computer.

Although the foregoing has been demonstrated and described in detail with reference to specific embodiments of this invention, it will be understood by those skilled in the art that various other changes can be made in form and detail without departing from its spirit and scope. It should be understood that when adapting to various embodiments of the invention, various changes can be made without departing from the broader concepts that are disclosed herein and which are covered by the claims below.

Claims (23)

1. The means of calculating the parameters, designed to calculate the parameters (508, 510) of the mixing with an increase in the number of channels to perform mixing with an increase in the number of channels of a signal (522), mixed with a reduction in the number of channels, in a stereo representation (524) of a multi-channel signal having a larger number channels than the signal (522), mixed with a reduction in the number of channels, and fewer channels than the multichannel signal, and the stereo representation (524) is a res the ultat of the left-side mixing of a multi-channel signal with a reduction in the number of channels and the right-side mixing (522) of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a reduction in the number of channels has associated multi-channel parameters (504, 506) describing the spatial characteristics of the multi-channel signal, at this multi-channel signal contains channels that are not contained in the stereo representation (524), and multi-channel parameters contain information about channels that are not neighing in a stereo representation (524), the parameter calculation means comprises:
means (502) of recalculation of parameters, designed to calculate the parameters (508, 510) of mixing with an increase in the number of channels, including parameter (508) characterizing the level difference between channels (CLD), and parameter (510) of coherence between channels (ICC) , from multichannel parameters (504, 506) using parameters containing information about channels not contained in the stereo representation, while parameter (508), which characterizes the level difference between channels (CLD), contains energy information for left and right anal stereo representation and the parameter (510) of the coherence between channels (ICC) contains information on the correlation between the left channel and the right channel. 2. The parameter computing means according to claim 1, wherein the parameter recalculating means (502) is configured to use multi-channel parameters (504, 506) describing the properties of a channel signal or combination of channels of a multi-channel signal relative to another channel or other combination of channels of a multi-channel signal . 3. The parameter calculating means according to claim 2, wherein the parameter recalculating means (502) functions in such a way that it calculates the mixing parameters (508, 510) with an increase in the number of channels describing the same characteristics of the channel signal of the intermediate channel representation as multi-channel parameters (504, 506). 4. The parameter calculation means according to claim 1, wherein the parameter recalculating means (502) is configured to use parameters (504) characterizing the correlation (ICC), which contain information about the correlation, and parameters (506), characterizing the signal level (CLD), which contain information about the energy of a channel or combination of channels of a multi-channel signal relative to another channel or other combination of channels of a multi-channel signal. 5. The parameter calculation means according to claim 4, made in such a way that it uses multi-channel parameters of a multi-channel signal comprising a left front channel (LF) (2), a left channel (5) of surround sound (LS), and a right front channel (RF) ( 4), the right channel (6) of surround sound (RS) and the central channel (C) (3). 6. The means for calculating the parameters according to claim 5, in which the means (502) for recalculating the parameters operates in such a way that it calculates a parameter (508) characterizing the level difference between the channels (CLD), using:
the first parameter characterizing the level difference between the channels (CLD) (CLD0), which contains energy information for the combination of the left channel (5) surround sound (LS), the right channel (6) surround sound (RS) and a combination of the remaining channels of the multi-channel signal;
the second parameter characterizing the level difference between the channels (CLD) (CLD1), which contains energy information for the combination of the left front channel (LF) (2), right front channel (RF) (4) and center channel (C) (3) ;
the third parameter characterizing the level difference between the channels (CLD) (CLD2), which contains information about the energy for the left channel (5) surround sound (LS) and the right channel (6) surround sound (RS); and
the fourth parameter characterizing the level difference between the channels (CLD) (CLD3), which contains energy information for the left front channel (LF) (2) and the right front channel (RF) (4). 7. The means for calculating the parameters according to claim 6, in which the means (502) recalculation of parameters operates in such a way that calculates a parameter characterizing the level difference between the channels (CLD), according to the following formula:

where L ₀ and R ₀ are the normalized power values of the stereo output channels L (left) and R (right) (524) calculated by the following formulas:

,

,
where the power values of multichannel signals are obtained from parameters characterizing the level difference between channels (CLD), as follows:

,

,

,

8. The parameter calculating means according to claim 5, wherein the parameter recalculating means (502) operates in such a way that it calculates the coherence between channels (ICC) parameter (510) using:
the first parameter characterizing the level difference between the channels (CLD) (CLD0), which contains energy information for the combination of the left channel (5) surround sound (LS), the right channel (6) surround sound (RS) and a combination of the remaining channels of the multi-channel signal;
the second parameter characterizing the level difference between the channels (CLD) (CLD1), which contains energy information for the combination of the left front channel (LF) (2), right front channel (RF) (4) and center channel (C) (3) ;
the third parameter characterizing the level difference between the channels (CLD) (CLD2), which contains information about the energy for the left channel (5) surround sound (LS) and the right channel (6) surround sound (RS); and
a fourth parameter characterizing the level difference between the channels (CLD) (CLD3), which contains energy information for the left front channel (LF) (2) and the right front channel (RF) (4);
the first coherence parameter between channels (ICC) (ICC2), which contains information about the correlation between the left channel (5) of surround sound (LS) and the right channel (6) of surround sound (RS); and
a second channel-to-channel coherence parameter (ICC) (ICC3), which contains correlation information between the left front channel (LF) (2) and the right front channel (RF) (4). 9. The parameter computing means of claim 8, wherein the inter-channel coherence parameter (5C) (ICC) is calculated according to the following formula:

where the estimated value of p correlation is determined by the following expression:

Where

and 10. The means for calculating the parameters according to claim 5, in which the means for recalculating the parameters operates in such a way that it calculates a parameter (508) characterizing the level difference between the channels (CLD), using:
the first parameter characterizing the level difference between the channels (CLD) (CLD0), which contains information about the energy for the central channel (C) (3) and a combination of the remaining channels of the multi-channel signal;
the second parameter characterizing the level difference between the channels (CLD) (CLD1), which contains information about the energy for the combination of the left front channel (LF) (2) and the left channel (5) surround sound (LS), and for the combination of the right front channel ( RF) (4) and right channel (6) surround sound (RS);
channel coherence parameter (ICC) (ICC0), which contains information about the correlation between the central channel (C) (3) and the combination of the remaining channels of the multi-channel signal. 11. The means of computing the parameters of claim 10, in which the parameter (508), characterizing the level difference between the channels (CLD), is calculated according to the following formula:

where L ₀ and R ₀ are the normalized power values of the output stereo channels L (left) and R (right), calculated by the following formulas:

,

,
Where

and

and

12. The means for computing parameters according to claim 5, in which means (502) recalculation of parameters operates in such a way that calculates the parameter (510) coherence between channels (ICC) using:
the first parameter characterizing the level difference between the channels (CLD) (CLD0), which contains information about the energy for the central channel (C) (3) and a combination of the remaining channels of the multi-channel signal;
the second parameter characterizing the level difference between the channels (CLD) (CLD1), which contains information about the energy for the combination of the left front channel (LF) (2) and the left channel (5) surround sound (LS), and for the combination of the right front channel ( RF) (4) and right channel (6) surround sound (RS);
the first coherence parameter between channels (ICC) (ICC0), which contains information about the correlation between the central channel (C) (3) and a combination of the remaining channels of the multi-channel signal;
the second channel coherence parameter (ICC) (ICC1), which contains information about the correlation between the combination of the left front channel (LF) (2) and the left channel (5) surround sound (LS), and the combination of the right front channel (RF) (4 ) and the right channel (6) of surround sound (RS). 13. The means for computing parameters according to item 12, in which means (502) recalculation of parameters operates in such a way that calculates the value of coherence between channels (ICC) using the following formula:

where measure p of correlation is calculated according to the following formula:

Where

and

14. The parameter calculating means according to claim 1, wherein the parameter recalculating means (502) operates in such a way that it uses multi-channel parameters (504, 506) describing the presentation of the multi-channel signal over subbands. 15. The parameter calculation means according to claim 1, wherein the parameter recalculating means (502) operates in such a way that it uses complex-valued multi-channel parameters (504, 506). 16. A channel recovery tool having a parameter recovery means, which comprises:
means for calculating the parameters according to claim 1; and
means for mixing (520) with increasing the number of channels, intended to obtain a stereo representation (524) using the parameters (508, 510) mixing with increasing the number of channels and signal (522), mixed with a reduction in the number of channels. 17. A method for generating mixing parameters (508, 510) with an increase in the number of channels to perform mixing with an increase in the number of channels of a signal (522) mixed with a reduction in the number of channels into a stereo representation (524) of a multi-channel signal having a larger number of channels than the signal, mixed with a reduction in the number of channels, and fewer channels than a multi-channel signal, the stereo representation being the result of left-side mixing of a multi-channel a signal with a reduction in the number of channels and right-side mixing of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a decrease in the number of channels has associated multi-channel parameters (504, 506) describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels, not contained in the stereo representation, and multichannel parameters (504, 506) contain information about channels not contained in the stereo representation, the method of holds:
calculation of mixing parameters (508, 510) with an increase in the number of channels, including parameter (508) characterizing the level difference between channels (CLD) and coherence between channels (ICC) parameter (510) from multichannel parameters using parameters containing information on channels not contained in the stereo representation (524), while parameter (508), which characterizes the level difference between the channels (CLD), contains energy information for the left and right channels of the stereo representation, and parameter (510) Channel Interconnection Ratio (ICC) contains correlation information between the left channel and the right channel. 18. An audio receiver (600) of sound containing means (601) for calculating parameters for computing mixing parameters with an increase in the number of channels to perform mixing with an increase in the number of channels of a signal mixed with a reduction in the number of channels into a stereo representation of a multi-channel signal having a larger number channels than a signal mixed with a reduction in the number of channels and a smaller number of channels than a multi-channel signal, and stereo representation e is the result of left-side mixing of a multi-channel signal with a reduction in the number of channels and right-side mixing of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a reduction in the number of channels has associated multi-channel parameters describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels not contained in the stereo representation and multichannel parameters contain information about the channel crystals are not contained in the stereo representation parameters calculation means comprises:
means of parameter recalculation, designed to calculate the mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherence between channels (ICC), from multi-channel parameters using parameters containing channel information, not contained in the stereo representation, the parameter characterizing the level difference between the channels (CLD) contains information about the energy for the left and right channels of the stereo about representation, and the coherence between channels (ICC) parameter contains information about the correlation between the left channel and the right channel. 19. A method of receiving sound, including a method for generating mixing parameters with an increase in the number of channels for mixing with an increase in the number of channels of a signal mixed with a reduction in the number of channels, into a stereo representation of a multi-channel signal having a larger number of channels than a signal mixed with a reduction in the number of channels , and fewer channels than a multi-channel signal, and the stereo representation is the result of left-side mixing of many a channel signal with a reduction in the number of channels and right-side mixing of a multi-channel signal with a decrease in the number of channels, and a signal mixed with a decrease in the number of channels has associated multi-channel parameters describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels not contained in the stereo representation , and multichannel parameters contain information about channels not contained in the stereo representation, the method contains the following operation:
calculation of mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherence between channels (ICC), from multichannel parameters using parameters containing information about channels not contained in the stereo representation, when In this parameter, characterizing the level difference between the channels (CLD), contains information about the energy for the left and right channels of the stereo representation, and the coherence parameter between the channel E (ICC) contains information on the correlation between the left channel and the right channel. 20. A computer-readable digital storage medium having a computer program stored thereon containing program code, which, when executed on a computer, provides a method for generating mixing parameters with increasing the number of channels for mixing with increasing the number of channels of a signal mixed with a reduction in the number of channels into stereo representation of a multi-channel signal having a larger number of channels than a signal mixed with a reduction in the number of channels, and fewer channels than a multi-channel signal, and the stereo representation is the result of left-side mixing of a multi-channel signal with a reduction in the number of channels and right-side mixing of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a reduction in the number of channels has associated multi-channel parameters describing spatial characteristics of a multi-channel signal, while the multi-channel signal contains channels that do not contain I stereo presentation, and multi-channel parameters include information on the channels not included in the stereo representation, the method comprising the step of:
calculation of mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherence between channels (ICC), from multichannel parameters using parameters containing information about channels not contained in the stereo representation, when In this parameter, characterizing the level difference between the channels (CLD), contains information about the energy for the left and right channels of the stereo representation, and the coherence parameter between the channel E (ICC) contains information on the correlation between the left channel and the right channel. 21. A computer-readable digital storage medium having a computer program stored thereon containing program code, which, when executed on a computer, provides an implementation of a method for receiving or reproducing sound, including a method for generating mixing parameters with an increase in the number of channels for mixing with an increase in the number of signal channels mixed with a reduction in the number of channels into a stereo representation of a multi-channel signal having a larger number of channels than a channel mixed with a reduction in the number of channels and a smaller number of channels than a multi-channel signal, the stereo representation being the result of a left-side mixing of a multi-channel signal with a reduction in the number of channels and a right-side mixing of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a reduction in the number of channels has multi-channel parameters associated with it, describing the spatial characteristics of a multi-channel signal, at this multi-channel signal contains channels not contained in the stereo representation, and multi-channel parameters contain information about channels not contained in the stereo representation, the method comprises the following operation:
calculation of mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherency between channels (ICC), from multichannel parameters using parameters containing information about channels not contained in the stereo representation, when In this parameter, characterizing the level difference between the channels (CLD), contains information about the energy for the left and right channels of the stereo representation, and the coherence parameter between the channel E (ICC) contains information on the correlation between the left channel and the right channel. 22. A sound reproducing apparatus (600) comprising parameter calculating means (601) for calculating mixing parameters with an increase in the number of channels for performing mixing with an increase in the number of channels of a signal mixed with a reduction in the number of channels into a stereo representation of a multi-channel signal having a larger number channels than a signal mixed with a reduction in the number of channels, and a smaller number of channels than a multi-channel signal, and the stereo the representation is the result of left-side mixing of a multi-channel signal with a reduction in the number of channels and right-side mixing of a multi-channel signal with a reduction in the number of channels, and a signal mixed with a reduction in the number of channels has associated multi-channel parameters describing the spatial characteristics of the multi-channel signal, while the multi-channel signal contains channels not contained in the stereo representation and multichannel parameters contain inform tion of channels not contained in the stereo representation parameters calculation means comprises:
means of parameter recalculation, designed to calculate the mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherence between channels (ICC), from multi-channel parameters using parameters containing channel information, not contained in the stereo representation, the parameter characterizing the level difference between the channels (CLD) contains information about the energy for the left and right channels of the stereo about representation, and the coherence between channels (ICC) parameter contains information about the correlation between the left and right channels. 23. A method for reproducing sound, including a method for generating mixing parameters with an increase in the number of channels for mixing with an increase in the number of channels of a signal mixed with a reduction in the number of channels, into a stereo representation of a multi-channel signal having more channels than a signal mixed with a reduction in the number of channels , and fewer channels than a multi-channel signal, and the stereo representation is the result of a left-handed mix a multichannel signal with a reduced number of channels and right-side mixing of a multichannel signal with a reduced number of channels, and a signal mixed with a reduced number of channels has associated multichannel parameters describing the spatial characteristics of the multichannel signal, while the multichannel signal contains channels not contained in stereo presentation, and multichannel parameters contain information about channels not contained in the stereo presentation ii, the method comprises the following operation:
calculation of mixing parameters with an increase in the number of channels, including a parameter characterizing the level difference between channels (CLD), and coherence between channels (ICC), from multichannel parameters using parameters containing information about channels not contained in the stereo representation, when In this parameter, characterizing the level difference between the channels (CLD), contains information about the energy for the left and right channels of the stereo representation, and the coherence parameter between the channel E (ICC) contains information on the correlation between the left channel and the right channel.

Images